1. Field of the Invention
In rolling mill having a plurality of series-arranged rolling stands for rolling metallic blank material into wires, strips, bars and so forth, it is necessary to smoothly introduce and guide the material to the central mold portion of the roll. For this purpose, there are provided a guiding roller apparatus at the inlet side of the roll. One of the typical guiding roller device has a pair of main guide rollers and a pair of sub-guide rollers. In such a guiding roller device, it is necessary to adjust the clamping or compressing condition of the sub-guide rollers, in accordance with the clamping or compressing condition of the main rollers, when the compressing or squeezing condition of the main guide rollers is changed and adjusted.
The invention relates to an improvement in the pair of sub-guide rollers.
2. Description of the Prior Art
The basic concept of the technical field with which the invention is concerned will be described hereinunder. For the convenience's sake, a reference is made to FIGS. 1, 2 and 6. Referring to these Figures, the guiding roller apparatus for guiding a blank steel W to be rolled to the rolls R, R' of a roll stand has a pair of roller holders 2, 3 which are pivoted by pins 6, 7 so as to be swung around these pins such that they converge at points upstream or downstream from the pins as viewed in the direction of the material flow. These pair of roller holders 2, 3 have pairs of guide rollers such as a pair of main rollers 4, 5 and a pair of sub-rollers 41, 51. The guide rollers of each pair cooperate with each other to clamp the material W therebetween. The clamping force, the roller clearance and other conditions have to be adjusted to provide an effective and reasonable clamping and guiding, so as to satisfy various requirements such as prevention of falling down of the blank material, linear guiding of the blank material and so on.
Referring to FIG. 6, the relation between the main rollers 4, 5 and the sub-rollers 41, 51 in the conventional apparatus is such that, when the distance between the peripheral surfaces of the main rollers 4, 5 contacting the material W is l, the roller holders 2,3 swingable around the pin 6, 7 to converge at points upstream or down stream from the pins is swung as illustrated to converge at the opposite side of the rollers to the pins 6, 7, forming therebetween an angle .theta.. In this state, the distance l' between the peripheral surfaces of the sub-rollers is so large that the sub-rollers cannot make a contact with the material W. Consequently, the contact of the guide rollers is made uneven, and the satisfactory clamping by the plurality of pairs of the guide rollers cannot be performed.
Therefore, in the conventional rolling mill, means are mounted on respective sides of the roller holders, for independently adjusting the sub-rollers 41, 51. In such a rolling mill, it is necessary to adjust the roller clearance l' of the sub-rollers, at each time the clamping condition of the main rollers is changed, so that the clamping conditions of these rollers may correspond to each other. Such adjustment, however, requires a high degree of technique. At the same time, the overall breadth of the rolling mill is inconveniently increased due to the presence of the means for adjusting the sub-rollers 41, 51.